1. Field
The disclosed concept relates generally to electrical switching apparatus and, more particularly, to electrical switching apparatus, such as circuit breakers. The disclosed concept also relates to trip units for circuit breakers. The disclosed concept further relates to interface assemblies for circuit breaker trip units.
2. Background Information
Electrical switching apparatus, such as circuit breakers, provide protection for electrical systems from electrical fault conditions such as, for example, current overloads, short circuits, abnormal voltage and other fault conditions. Typically, circuit breakers include an operating mechanism which opens electrical contact assemblies to interrupt the flow of current through the conductors of an electrical system in response to such fault conditions as detected, for example, by a trip unit.
FIG. 1 shows a trip unit 2 having an interface assembly 4 with a number of adjustment knobs 6 (only one knob 6 is shown for ease of illustration)(see also, FIG. 2) that is accessible from the exterior of the circuit breaker (not shown). Due to space constraints, the adjustment knob(s) 6 is/are relatively small in size. The small size makes the adjustment knob(s) 6 difficult to see. Further, there is typically a significant amount of printed information 8 surrounding the adjustment knob(s) 6. For ease of illustration, only a limited amount of printed information 8 (see, for example, position indications “A,” “B,” “C,” “D,” “E,” and “F”) is shown in the example of FIGS. 1 and 2. It will be appreciated that there is typically a significant additional amount of printed information (not shown) on the label(s) 10 disposed on the interface assembly 4 around or near the adjustment knob(s) 6. This, in combination with the small knob size, makes accurately identifying the position of the knob(s) 6, and thus the setting of the trip unit 2, difficult. This is particularly true in relatively low light environments (e.g., without limitation, mining applications).
There is, therefore, room for improvement in electrical switching apparatus, such as circuit breakers, and in trip units and interface assemblies therefor.